A form of apparatus for decorating stiff objects, which can be considered representative in this respect, comprises a conveyor path, with holders displaceable along the conveyor path for moving the objects therealong. A plurality of treatment stations for treating the objects are disposed along the conveyor path, including at least one printing station for applying decoration to the articles and at least one drying station downstream of the printing station for drying ink applied to the objects. In that respect it is nowadays the usual practice to employ printing inks which dry comparatively quickly, for example under the effect of UV radiation.
In the case of multi-color printing the procedure adopted is frequently such that partial print images involving different colors are applied to the object in successive printing steps, for example using a screen printing process. The totality of those partial print images which are printed one within the other then affords the overall print image. When using such a printing process, it is normally necessary, after each printing operation for producing a partial print image, for that partial print image to be dried before the next partial print image is applied or the object can be handled in some other fashion. Accordingly, such an apparatus as outlined above generally has a respective drying station arranged downstream of each printing station in the direction of transportation movement of the objects through the apparatus, for drying the printing ink applied in the printing station upstream of each such drying station.
When using UV radiating devices in the drying stations, precautions possibly have to be taken to screen the area around the individual drying stations from the UV radiation.
It will be seen that a printing machine of the general structural configuration referred to above will usually require a considerable amount of space as multi-color printing is implemented by means of a machine comprising three, five or more printing stations and thus a corresponding number of drying stations. It will be appreciated that this requires a conveyor path of corresponding length which thus makes the machine very long when the path is a linear path or, when the machine is of a turntable kind involving a circular conveyor path along which the object holders are displaced, the arrangement will be of a correspondingly large diameter. Not only is the amount of space required very great but transportation and servicing of the machine are also made more difficult.